A Method Of Adjusting Measurements Of External Grid Based On Predictor-Corrector Algorithm

One of the trends of development of modern power system is grid interconnection. Objectively, the impact of large-scale wind power requires that each control center can do integrated calculating and analysis of the entire grid. Urgent need to address is the multi-control integrated modeling among different centers. One of the solutions is using asynchronous iterative distributed computing model to build an integrated-distributed model which is based on virtual link approach. in the process of distributed state estimation on the integrated-distributed model, a priority issue is to solve the boundary estimation error.When each control center calculated independently, state estimation gets real-time data of each of the local power grid and is calculated according to a certain period. There may be sampling time difference among different control centers, then the measurement section provided to state estimation may exist time difference, which will bring greater estimation error to outside grid and increase difficultiesFor the problem of external estimation error which is caused by time differences existing between different measurement sections, when distributed state estimation of the entire network is started, this paper proposes an external network measurement sampling error correction methods according to Predictor-Corrector. Before distributed state estimation, the measurement data of each control center except the target system should be corrected to reduce the impact of boundary estimation error. The method uses the feature that EMS (energy management system) of adjacent subsystems is often modeled overlap in the boundary region and the boundary overlap nodes own different values, to predict the time difference of the two measurement sections. Then use linear extrapolation to fit the measurement changing curves, correct the measurements of external network according to time difference and the measurement changing curves. Ensure all measurement sections are at the same time when distributed state estimation is started, to increase the accuracy of the calculation. In this paper, data of Xingtai grid is used as an example to verify the validity of the method.